Our Phase 1 research program seeks to develop a continuous, non- invasive, on-line process for monitoring levels of urea in a patient's blood during hemodialysis. We propose to utilize low-resolution Raman scattering for direct measurement of the urea levels in blood using the optical access provided in the tubing delivering the patient's blood to the dialyzer. Our past and preliminary results have shown that urea has a unique Raman spectroscopic signature and can be identified and quantified against a whole blood background. The ultimate goal of such a process would to provide a direct and continuous measure of the efficiency of dialysis without having to wait for the drawing of a blood sample, providing for the first time an assessment of whether dialysis at any point in time has reached an effective stopping point for the patient, as well as providing an ongoing readout of the effectiveness of the dialysis system during patient treatment. The Phase 1 program is designed to assess the capability of low resolution Raman to quantify the levels of urea in canine blood samples with varying concentrations of urea present. Phase 2 would expand the evaluation process to human blood analysis during actual dialysis procedures. PROPOSED COMMERCIAL APPLICATIONS: Is successful, a Raman measurement approach would, for the first time, provide a device that would allow real-time, continuous monitoring of the progress of urea removal during the course of hemodialysis. Such a device would be directly integrated into the dialyzer in commercial application.